Pouch for packaging flowable materials

Abstract

An environmentally friendly polymer film pouch made from a polyethylene film structure for the packaging of flowable materials, for example milk, including, for example, a pouch made from a multilayer film structure such as a two-layer or a three-layer coextruded film containing at least one layer of ultra low density linear polyethylene, as a seal layer.

What is claimed is: 
     
       1. A process for preparing a pouch containing a flowable material comprising forming a film structure by either blown tube extrusion or cast extrusion, forming the film structure into a tubular member and transversely heat-sealing opposite ends of the tubular member, said tubular member comprising a film structure for a pouch container comprising (a) from 10 to 100 percent by weight of at least one polymeric seal layer of an ultra low density linear ethylene copolymer interpolymerized from ethylene and at least one alpha-olefin in the range of C 3  -C 10  and having (1) a density of from about 0.89 g/cm 3  to less than 0.915 g/cm 3 , (2) a melt index of less than about 10.0 g/10 minutes and (3) (i) a hot tack or heat seal initiation temperature of less than 100° C. at a force of at least 1N/inch (39.4N/m) or (ii) achieving a hot tack strength of at least 1N/inch (39.4N/m) at a seal bar temperature of about 110°  C. at less than 0.2 seconds using the DTC Hot Tack Strength Method or achieving a heat seal strength of at least 1 lb f  /inch (175N/m) at a seal bar temperature of about 110° C. at less than 0.25 seconds using the DTC Heat Seal Strength Method; and (b) from 0 to 90 percent by weight of at least one polymer selected from the group consisting of a linear copolymer of ethylene and a C 3  -C 18  -alpha-olefin having a density of greater than 0.916 g/cm 3  and a melt index of from 0.1 to 10 g/10 minutes, a high-pressure low density polyethylene having a density of from 0.916 to 0.930 g/cm 3  and a melt index of from 0.1 to 10 g/10 minutes and ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate from 2.2:1 to 24:1 and a melt index of from 0.2 to 10 g/10 minutes. 
     
     
       2. A process for preparing a pouch containing a flowable material comprising forming a film structure by either blown tube extrusion or cast extrusion, forming the film structure into a tubular member and transversely heat sealing opposite ends of the tubular member, said tubular member comprising: (I) (a) from 10 to 100 percent by weight of at least one polymeric seal layer of an ultra low density linear ethylene copolymer interpolymerized from ethylene and at least one alpha-olefin in the range of C 3  -C 10  and having (1) a density of from about 0.89 g/cm  3  to less than 0.915 g/cm 3 , (2) a melt index of less than about 10.0 g/10 minutes and (3) (i) a hot tack or heat seal initiation temperature of less than 100° C. at a force of at least 1N/inch (39.4N/m) or (ii) achieving a hot tack strength of at least 1N/inch (39.4N/m) at a seal bar temperature of about 110° C. at less than 0.2 seconds using the DTC Hot Tack Strength Method or achieving a heat seal strength of at least 1 lb f  /inch (175N/m) at a seal bar temperature of about 110° C. at less than 0.25 seconds using the DTC Heat Seal Strength Method; and (b) from 0 to 90 percent by weight of at least one polymer selected from the group consisting of a linear copolymer, of ethylene and a C3-C18-alpha-olefin having a density of greater than 0.916 g/cm 3  and a melt index of from 0.1 to 10 g/10 minutes, a high-pressure low density polyethylene having a density of from 0.916 to 0.930 g/cm 3  and a melt index of from 0.1 to 10 g/10 minutes and ethylene-vinyl acetate copolymer having a weight ratio of ethylene to vinyl acetate from 2.2:1 to 24:1 and a melt index of from 0.2 to 10 g/10 minutes; and   (II) at least one layer of a linear low density ethylene-C 3  -C 18  -alpha-olefin copolymer having a density of from about 0.916 to about 0.935 and a melt index of from about 0.1 to about 10 g/10 minutes.   
     
     
       3. The process of claim 2 wherein the film structure includes: (III) at least one layer of a high-pressure polyethylene having a density of from 0.916 to 0.930 g/cm 3  and a melt index of from 0.1 to 10 g/10 minutes.